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# Dynamically selecting from multiple retrievers

This notebook demonstrates how to use the `RouterChain` paradigm to create a chain that dynamically selects which Retrieval system to use. Specifically we show how to use the `MultiRetrievalQAChain` to create a question-answering chain that selects the retrieval QA chain which is most relevant for a given question, and then answers the question using it.

import CodeBlock from "@theme/CodeBlock";
import MultiRetrievalQAExample from "@examples/chains/multi_retrieval_qa.ts";

import IntegrationInstallTooltip from "@mdx_components/integration_install_tooltip.mdx";

<IntegrationInstallTooltip></IntegrationInstallTooltip>

```bash npm2yarn
npm install @langchain/openai
```

<CodeBlock language="typescript">{MultiRetrievalQAExample}</CodeBlock>
